The present invention relates broadly to the destruction of organic compounds in aqueous solutions. More specifically the invention relates to destruction of organics in an aqueous solution by oxidation in the presence of a catalyst system.
Disposal of aqueous wastes containing relatively high concentrations of organic compounds presents a difficult pollution problem. One approach to the solution of this problem is to decompose the organic components by biological degradation. This involves providing micro-organisms capable of decomposing the organic and large ponds or particulate piles to give the micro-organisms access to oxygen and a surface on which to operate.
However, there are serious drawbacks to the use of such biological processes. First, the micro-organisms generally digest only organics of relatively low concentration, so that most aqueous waste streams must be diluted before exposure to the micro-organisms. Second, many organic components are non-biodegradable or even toxic to the micro-organisms. Obtaining an appropriate micro-organism for use on a given aqueous waste stream may be very difficult. Finally, many of the waste streams contain brines, which not only inhibit biological processes, but also require further treatment to remove dissolved or suspended solids before discharge into public waters.
Another approach is to utilize "wet combustion" reactions which involve treating the aqueous waste with air under conditions of high pressure and temperature. Containers constructed of special materials are required to withstand the high temperatures and pressures developed. Furthermore, since the fuel value of many aqueous wastes is low, heat recovery through heat exchangers constructed of special materials is advisable to obviate the need for large external additions of heat.
Consequently, there is need for a catalytic system which permits wet combustion reactions to take place at substantially lower operating temperatures and pressures. This would ease the demands on materials of construction and extend the utility of wet combustion to include streams containing lower concentrations of organics since less inherent fuel value or external additions of heat would be required to sustain the reaction. Desirably the catalyst system should be operable in brine systems and should not itself contaminate the purified waste stream.